Hydraulic Lift and Soil Nutrient Heterogeneity

Water released at night from roots into upper portions of the soil profile in the process of hydraulic lift may contribute to reducing spatial soil nutrient heterogeneity. A manipulative field experiment was conducted in a semiarid shrub stand to determine if circumvention of hydraulic lift, by nighttime illumination of the shrub canopy, would result in greater soil nutrient heterogeneity than if the hydraulic lift process was allowed to operate. Nutrient-enriched patches were superimposed on the existing soil heterogeneity and after 40 days, the patches and interspaces were sampled for ions of different mobility and for root mass. There was no indication under these conditions that hydraulic lift was contributing to smoothing spatial nutrient heterogeneity

Histone H3.3 beyond cancer: Germline mutations in Histone 3 Family 3A and 3B cause a previously unidentified neurodegenerative disorder in 46 patients

Although somatic mutations in Histone 3.3 (H3.3) are well-studied drivers of oncogenesis, the role of germline mutations remains unreported. We analyze 46 patients bearing de novo germline mutations in histone 3 family 3A (H3F3A) or H3F3B with progressive neurologic dysfunction and congenital anomalies without malignancies. Molecular modeling of all 37 variants demonstrated clear disruptions in interactions with DNA, other histones, and histone chaperone proteins. Patient histone posttranslational modifications (PTMs) analysis revealed notably aberrant local PTM patterns distinct from the somatic lysine mutations that cause global PTM dysregulation. RNA sequencing on patient cells demonstrated up-regulated gene expression related to mitosis and cell division, and cellular assays confirmed an increased proliferative capacity. A zebrafish model showed craniofacial anomalies and a defect in Foxd3-derived glia. These data suggest that the mechanism of germline mutations are distinct from cancer-associated somatic histone mutations but may converge on control of cell proliferation

Nutrient Uptake from Enriched Soil Microsites by Three Great Basin Perennials

Relative nutrient uptakes efficiency was measured using a dual—radiotracer (32P and 33P) technique for Agropyron desertorum, Artemisia tridentata, and Pseudoroegneria spicata, species from the arid shrub—steppe of the Intermountain Region in the western U.S. These species differed in the timing and magnitude of their response to experimentally enriched soil microsites. The most rapid and significant increase in the uptake of phosphorus tracer from enriched microsites was exhibited by Agropyron, followed by Artemisia, while there was only a trend toward an increase in uptake for Pseudoroegneria. The volume of soil enriched was only 4% of the total pot volume yet Agropyron extracted more phosphorus from the enriched microsite than was removed from the remainder (96%) of the soil volume based on tracer uptake from enriched and unenriched microsites. For Agropyron and Pseudoroegneria, plant uptake of phosphorus from microsites was approximately proportional to the soil microsite enrichment and all three species exhibited increased root length density within the microsites in proportion to the concentration of available nutrients. Integrated physiological and morphological response of the plants to nutrient enrichment increased phosphorus uptake, normalized to the amount of phosphorus available in the soil microsites, by 19.7 to 97.5 x compared to uptake from a similar volume of unenriched soil. Preferential allocation of recently assimilated carbon to roots within enriched soil microsites was also demonstrated. The most important differences detected among species were associated with the temporal flexibility they exhibited in response to enrichment of soil microsites. Differences in flexibility and response among these species have been reported for other aspects of nutrient uptake, suggestive of species—specific differences contributing to demonstrated differences in productivity, persistence, and competitive ability

The Means of Management Control

In the understanding of managerial control over work, the labour process literature has been very influential. Recent critical contributions from the sociological tradition have, however, served to so fragment the underlying perspective that its coherence is now threatened. This paper seeks to demonstrate how a dialectical analysis can lay the basis for a viable amended approach. The need for a dialectical framework has often been urged - illustrations of such a perspective in operation, however, are rare. Using a series of examples, this paper argues that the dialectic of work control can be revealed by focussing on two phenomena: the 'levels' and 'circuits' of control